Working on replacing the timing chain gasket on my 99 ford explorer 5.0

got to the point of some seized bolts and not sure what to do.

using a big blow torch sounds like it would work best but I don’t have one and I don’t want to strip my motor down enough to do it safety.

After a while I remembered inductive heating. Fortunatly there is a tool for that! Unfortunatly it is like $500. But it works really well!

After some more thinking I decided to go more of the DIY route and bought this for $13.
https://www.amazon.com/gp/product/B01GDVVANA/

I needed a power supply so I grabbed an old PC power supply. Using some yellow 12 volt wires and the black ground wires. Needed to add a power button by bridgeing the green and black wires on the 20 pin connector
* http://www.tomshardware.com/forum/198025-28-turning-power-supply
* http://case-mods.linear1.org/case-mod-101-the-atx-power-switch-demystified/

Yay it heats up a paper clip to red hot in about 8 seconds!

I needed some sort of project case to use in the actual repair!

The bolt I needed to heat up was larger then a paperclip so it took longer to heat up. Doing a bench test after about 2 minutes I was able to get the bolt to about 600 degrees!

In the end I couldn’t generate enough heat when the bolt was in the block using the $13 inductive heating unit. A $55 handheld torch did the job.

I have been experimenting with tasseract and occasionally get really terrible results when I know I should not. When I grab the images, change the dpi aka save them at a different resolution I get great results.

Tasseract wants 300 dpi. when I google dpi of digital images or how to change dpi on android most of the information is along the lines of “you dont want dpi, you dont know what you are talking about, your life is a lie and nobody cares about you”. So what is going on here?

Is there a Minimum Text Size? (It won’t read screen text!)
There is a minimum text size for reasonable accuracy. You have to consider resolution as well as point size. Accuracy drops off below 10pt x 300dpi, rapidly below 8pt x 300dpi. A quick check is to count the pixels of the x-height of your characters. (X-height is the height of the lower case x.) At 10pt x 300dpi x-heights are typically about 20 pixels, although this can vary dramatically from font to font. Below an x-height of 10 pixels, you have very little chance of accurate results, and below about 8 pixels, most of the text will be “noise removed”.

So it looks like they want the letters to be within a certain range of pixels tall. They only give minimum pixels here, around 20 pixels minimum. But I believe there is also a maximum pixel height they will look for. In my previous post ‘tesseract’ small unclear text was picked up reliably but large very clear text was ignored. From what I can find on google it does not appear there is a configured maximum but a algorithm that tries to determine it based on picture height.

My current image is 115 x 59 and the text is about 1/3 of that height or about 19 to 20 pixels high. It seems silly to my that doubling the pixels in the picture with no quality improvement would yield better results but I guess I can give it a try.

So my next steps will be

Make sure my text is above the minimum pixel xheight by a safe margin

study up more on the max height algorithm. maybe I just need to zoom out?

build simple-android ocr
git clone https://github.com/GautamGupta/Simple-Android-OCR.git Simple-Android-OCR
go change target version in properties file
point the project at the tess two install path

I had trouble getting my phone to allow the debug connection. “adb devices” would either return nothing or the device serial number as question marks or the status as unauthorized. I tried several combinations of restarting adb along with restarting the phone, unplugging and replugging, disabling / enabling dev mode. I think is what finally did it was removing all currently authorised computers from my phone.

So my guess is the letters are too big compared to the size of the picture. Tesseract is really geared towards looking at a page of text so it would make sense to ignore larger patterns and focus on smaller ones.

Most of the groovy packages are broken including rosserial. Short version of building from source:
cd ~/overlay_ws/src
git clone git://github.com/ros-drivers/rosserial.git
cd ~/overlay_ws/
catkin_make
source ~/overlay_ws/devel/setup.bash

This should be pretty straight forward but unfortunately the package is broken. Groovy is supposed to use .rviz configuration files for rviz instead of the older .vcg files. The urdf_tutorials were never properly tested or groovy changed sometime after urdf_tutorials were released.

so it looks like that gatewayTest.py is trying to extend itself, repeatedly. I’ll move the test out of the package so when the test tries to load the package it doesn’t try to load itself which would try to load the package which would load itself.

/serverSupport
__init__.py
gateway.py

/gatewayTest.py

This works! but it would rather keep the tests in their own directory or with the package..